Disable skipValidation when context is lost. Lost no-error contexts should gracefully handle GetProgramiv, etc. Includes test that a lost no-error context doesn't crash on getProgramiv. Firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1601703 Bug: angleproject:4244 Change-Id: I8c37df37e83308ab85ad958df6dab46b0ab348e1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2003239 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>